This invention relates to a hydrocarbon hydrogenation catalyst composition, a process of treating a hydrogenation catalyst composition, and to a hydrogenation process employing such hydrogenation catalyst composition.
It is known to one skilled in the art that a less unsaturated hydrocarbon compound can be produced by a thermal cracking process. For example, a fluid stream containing a saturated hydrocarbon such as, for example, ethane, propane, butane, pentane, naphtha, and the like and combinations thereof can be fed into a thermal (or pyrolytic) cracking furnace. Within the furnace, the saturated hydrocarbon is converted to an unsaturated hydrocarbon compound such as, for example, ethylene or propylene. Such unsaturated hydrocarbons are an important class of chemicals that find a variety of industrial uses. For example, ethylene can be used as a monomer or comonomer for producing a polyolefin. Other uses of unsaturated hydrocarbons are well known to one skilled in the art.
However, unsaturated hydrocarbons produced by a thermal cracking process generally contain an appreciable amount of less desirable highly unsaturated hydrocarbon(s) such as alkyne(s) or diolefin(s). For example, ethylene produced by thermal cracking of ethane is generally contaminated with a highly unsaturated hydrocarbon, such as acetylene, which must be selectively hydrogenated to a less unsaturated hydrocarbon, such as ethylene, but not to a saturated hydrocarbon such as ethane, in a hydrogenation process.
In addition, catalyst compositions comprising palladium and an inorganic support, such as alumina, are known catalyst compositions for the hydrogenation of highly unsaturated hydrocarbons such as alkynes and/or diolefins. For example, U.S. Pat. No. 4,484,015 discloses the use of a palladium and silver catalyst composition supported on alumina for the selective hydrogenation of acetylene to ethylene. Also for example, U.S. Pat. No. 5,510,550 discloses the use of a palladium, silver, and alkali metal catalyst composition supported on alumina for an even more selective hydrogenation of acetylene to ethylene. The operating temperature for the hydrogenation process is selected such that essentially all highly unsaturated hydrocarbon such as alkyne (e.g., acetylene) is hydrogenated to its corresponding less unsaturated hydrocarbon such as alkene (e.g., ethylene) thereby removing the alkyne from the product stream while only an insignificant amount of alkene is hydrogenated to a saturated hydrocarbon such as alkane (e.g., ethane). Such selective hydrogenation process minimizes the loss of desired less unsaturated hydrocarbons.
Thus, the development of a catalyst composition, a process of treating such catalyst composition, and a process of using such catalyst composition for the hydrogenation of highly unsaturated hydrocarbons such as diolefins (alkadienes) or alkynes to less unsaturated hydrocarbons such as monoolefins (alkenes) where such catalyst composition has improved selectivity, increased activity, and/or longer operating life would be a significant contribution to the art and to the economy.